Construction of banjos and analogous apparatus



July 9, 1929. vr GRAU CONSTRUCTION OF BANJOS AND ANALOGOS APPARATUS Filed July' 13, 1925 Patented July 9, 1929.

UNITED srivrlssA VINCENT GRAU, OF PARIS, FRANCE.

CONSTRUCTION OF BANJ'OS AND ANALOGOUS APPARATUS.

Application led July 13, 1925, Serial No. 43,342, and in France May 5, 1925.

The present invention lrelates to banjos yand similar apparatus and its object is to provide improved means'for securing the base bar oi'Y the neck to the body oi' the instruinent and by which deformation of the resonance box or of the cylinder supporting the Vdiaphragm is prevented.

According to the present invention the resonance box or the cylinder supporting the diaphragm is reinforced-in the interior of the box by a cross piece, which is tubular and which is disposed diainetrically of the box in such manner as to avoid the deformation of the box when litting the base bar and during the subsequent working. The base bar of the neck traverses this cross piece and is fixed by screws at a point of the box, diametrically opposed to the point of application of the base bar of the neck. In this way, when actuating the screw fixing the base bar, the cross piece undergoes compression but the 'box cannot undergo deformations. This enables me to secure a resonance box which is not deformable. Furthermore, the strings which may be iixed on one side at' the extremity of the cross piece on an appropriate support and on the other side to the neck, cannot loosen themselves accidentally and change the tonality because their two end points remain constantly lixed. The reinforcing cross piece of the resonance box may either sheath the base bar of the neck or keep the same laterally, Aand may be readily applied to different types of existing banjos.

One executional mode of the subject matter of the invention is represented in the drawings appended.

Figure 1 is a central sectional view through the box oi' the banjo, showing the means for fixing the base bar and the cross piece.

Figure 2 illustrates adetail, namely the box and its cross piece in elevation.

Figure 3 a transverse section through the cross piece, the section being taken according to lines a-a of Figure 2.

Figure 4 is a plan view illustrating the application of the device to a banjo.

1 is the resonance box and 2 the resonance bottom, 3 the neck, 4 its heel and 5 its base bar. The neck 3 is arranged with the entire inner surface of the heel bearing directly on the box. The base bar 5 forming one piece with the neck traverses the box diametricall'y and is xed at its outer extremity bv means of a screw Gland ay supporting y washer 7, to the box. l

When tightening the screw 6, the box will tend to be crushed or to become oval and hence also tend to cause an "irregular distention of the diaphragm and of the strings.

the" box and has Vshoulders 9 and 10fwhich. bear against the inner surface of the wall of the box at its two diametrically opposite points. The y. tubular ,cross piece may b e square, as represented in Figure', or round, polygonal' or other form. The base bar 5 extends through this cross piece from one end to the other and is of such size and shape as to tit snugly in the cross piece. The cross piece may be put in place very readily and rapidly. In practice two notches are made in the inner surface of the box 'for the reception of the two shoulders 9 and l0 which are fixed thereafter to the box by means of regulating screws 11. The base bar 5 is put under longitudinal tension by the screw 6, .and the cross piece is put under compression and transmits stress directly to the heel 4 of the base bar and hence prevents deformation of the box, as will be understood.

The shoulder 9 of the cross piece 8 has a projection 12 arranged for the mounting of an appropriate device 13 for ixing the strings 14 at their extremities, and hence the tension of the strings is transmitted to the cross piece 8 and the box 1 is relieved thereof. The strings are thus prevented from becoming casually lax, are prevented Jfrom changing their tonality, and the diaphragm 15 remains'unitormly stretched. The box 1 may be very light, because it does not undergo an effect of diametric compression and cannot tend to become oval.

The adaptation of the cross piece 8 is possible on all existing types of French or American banjos with simple or double body, whatever be the method of tension of the diaphragm 15 on its circle of wood.

In the example ol' Fig. 1, the banjo is supposed to be of the double body type 1 16, the circle of wood 16 lits in then at the interior of the resonance body 1 and shows a notch at the right side of the passage of the cross piece 8.

The cross piece 8 may also be adapted as shown in Fig. 4, on a special banjo of the ing a shoulder bearing against the body and Clavero7 type, provided according to the French patent of invention No. 496,281 of Y February 26, 1919, with a tension system for the diaphragm comprising a screwing column 17 in the form of a corner penetrating into a circularpassage of the circle of Wood 16, cut in U-form, to retain the pad of the diaphragm.

Modifications of the details of the construction may be made Within the scope of the appended claims. y

What I claim, is y 1. In a stringed musical instrument a body, a neck and a tubular cross piece arranged in line with the neck, extending diametrically across the body and provided at its ends With shoulders Which bear against `the inner side of the Wall of the body at diametrically opposite points, said shoulders being provided With adjusting screws Which engage the Wall of the body, said neck havprovided with a brace bar Which extends across the body and is enclosed within said cross piece, and a screw extending through the wall of the body and into said brace bar so that the body is braced against distortion by the tension of the strings.

2. In a stringed musical instrument a body, a neck and a cross piece arranged in line with the neck, extendingV diametrically across the body and provided at its ends With shoulders Which bear against the inner side of the Wall of the body at diametrically opposite points, said shoulders being provided with adjusting screws Which engage the Wall of the body, one of said shoulders, at-

the side of the body opposite the neck, being provided with means for the connection o1 'the strings thereto so that the tension of the strings is imposed only on the neck and the cross piece and distortion oit Vthe body is prevented.

In Witness whereof I ailix my signature.

VINCENT GRAU. 

